This invention relates generally to an X-ray system tester and more particularly to an X-ray system tester adapted to measure a variety of operating parameters of an X-ray system and provide information to an X-ray equipment technician to enable such technician to test the X-ray equipment and ensure that such equipment operates properly and in accordance with certain safety requirements.
It is well known in the prior art that an X-ray beam emanating from an X-ray tube may be passed through a selected portion of a patient to produce a shadow image of the internal structure of the patient on an aligned X-ray film. The quality of the X-ray image is dependent upon the intensity of the X-ray flux which in turn, is proportional to X-ray tube anode current (mA) and to the time duration of the X-ray exposure.
The product of average anode current and X-ray exposure time duration yields an exposure quantity milliampere-seconds parameter sometimes referred to as (MAS). The parameter MAS must be large enough on the one hand to provide the desired X-ray image on the film while small enough on the other hand to protect the patient from excessive exposure to X-radiation and also protect the X-ray target from damage due to excessive heat.
Further, the quality of the X-ray shadow image is also dependent upon the penetrating ability of the X-ray beam. In operation, electrons emitted from the cathode are beamed electrostatically onto a focal spot area of an anode target with sufficient energy to generate X-rays which emanate from the anode target in a beam. The maximum energy of X-rays in the beam is proportional to the maximum kinetic energy obtained by the beamed electrons emitted from the cathode, which is a function of the voltage applied between the cathode and anode electrodes during operation of the tube. Consequently, if the selected portion of the patient is comprised of fleshy tissue the voltage applied between the cathode and anode electrodes of the X-ray beam should be relatively low in order to generate correspondingly low energy, or soft, X-rays since soft X-rays have sufficient energy to penetrate through the fleshy tissue in the selected portion and produce on the aligned film an X-ray having the desired resolution and contrast for defining detail structure. Conversely, if the selected portion of the patient is comprised of bony structure, the voltage applied between the cathode and anode electrodes should be relatively high in order to generate sufficiently high energy, or hard, X-rays which can penetrate through the more dense bony structure.
Further, the quality of the X-ray image is also related to the filament current of the X-ray tube because the anode current is a function of such filament current and the anode current establishes the X-ray flux intensity of the tube.
Still further, the quality of the X-ray image is dependent upon the regulation of the supply or line voltage supplied to the X-ray generator during an exposure interval. That is during an interval of operation of the X-ray tube the X-ray tube presents a load to the X-ray generator, which may cause a drop in line voltage. This drop in line voltage causes reductions in both anode current and the peak voltage across the anode and cathode electrodes. Thus, in order to determine if the equipment has the desired anode-cathode voltage and anode current when the equipment is in actual operation it is necessary to take into account the loading effect of the equipment on the supply.